Radio communication method and a base station and user terminal thereof

Abstract

A radio communication system where a terminal transmits a data signal to a base station using data transmission band frequencies assigned by the base station, and performs time-division multiplexing of a pilot signal with the data signal and transmits the resulting signal to the base station. Including deciding a pilot transmission band for the user terminal covering the data transmission band of the user terminal by frequency offset; and instructing the user terminal to transmit the pilot signal using the decided pilot transmission band. A CAZAC sequence is used as the pilot signal. The instructing includes calculating a frequency offset amount for the user terminal, and a cyclic shift amount of the CAZAC sequence and the frequency offset amount; instructing the user terminal to perform cyclic shift of the CAZAC sequence by the cyclic shift amount, and perform frequency offset of the pilot transmission band by the frequency offset amount.

What is claimed is: 
     
         1 . A radio communication method in a radio communication system in which each of user terminals together with transmitting a data signal to a base station using different data transmission band frequencies that are assigned by the base station, performs time-division multiplexing of a pilot signal with the data signal and transmits the resulting signal to the base station, comprising:
 deciding a pilot transmission band for each user terminal so that the pilot transmission band covers the data transmission band of the user terminal by frequency offset; and   instructing each user terminal to transmit the pilot signal using the frequencies of said decided pilot transmission band wherein a CAZAC sequence is used as said pilot signal, wherein said instructing comprises:   calculating an amount of said frequency offset for each user terminal, and an amount of cyclic shift of the CAZAC sequence and the amount of the frequency offset; and   instructing each user terminal to perform cyclic shift of said CAZAC sequence used as the pilot signal by the cyclic shift amount, and perform frequency offset of the pilot transmission band by said frequency offset amount.   
     
     
         2 . A base station in a radio communication system, in which each of user terminals together with transmitting a data signal to a base station using different data transmission band frequencies that are assigned by the base station, performs time-division multiplexing of a pilot signal with the data signal and transmits the resulting signal to the base station, comprising:
 a resource management unit that decides a pilot transmission band for each user terminal so that the pilot transmission band covers the data transmission band of the user terminal by frequency offset, and instructs the user terminal to transmit a pilot signal using the frequencies of said decided pilot transmission band wherein a CAZAC sequence is used as said pilot signal, and wherein   said resource management unit comprises:
 a cyclic shift amount calculation unit that calculates an amount of said frequency offset for each user terminal, and an amount of cyclic shift of the CAZAC sequence and the amount of the frequency offset; and 
   an instruction unit that together with instructing each user terminal to perform a cyclic shift of said CAZAC sequence used as the pilot signal by the calculated cyclic shift amount, instructs each user terminal to perform frequency offset of the pilot transmission band by said frequency offset amount.